Lithium battery separator film tensile test

Abstract: This article presents an example of tensile testing of lithium battery separator samples using the Kunpeng BOYI 2025 electronic universal testing machine. This example is mainly used to evaluate the mechanical properties of lithium battery separators and can provide reliable data for product development, quality management, manufacturing process settings, and performance identification.

Keywords: BOYI 2025 Precision Universal Testing Machine Lithium Battery Separator Tensile Test

A lithium-ion battery is a secondary battery (rechargeable battery), which mainly works by lithium ions moving between the positive and negative electrodes. Lithium ion battery separator, in the structure of lithium batteries, the separator is one of the key internal components. For lithium battery series, because the electrolyte is an organic solvent system, it requires separator materials that are resistant to organic solvents. Separator materials generally use high-strength thin-film polyolefin porous membranes. 。 Requirements for lithium battery separators: 的要求：

(1) Have electrical insulation to ensure mechanical isolation of the positive and negative electrodes. (2) Have certain pore size and ；

porosity to ensure high ionic conductivity and good permeability lithium ions (3) Since the electrolyte solvent is a strongly polar organic compound ；

the separator must be corrosion-resistant and have sufficient chemical and electrochemical stability; the electrolyte (4) Good wettability with the electrolyte and sufficient liquid absorption and retention capacity; (5) Sufficient mechanical properties, including puncture strength, tensile strength

etc., but as thin as possible;

(6) Good dimensional stability and flatness; (7) Good thermal stability and automatic shutdown protection performance. Power batteries have higher requirements for separators, usually using composite membranes

(8) The separator's thermal shrinkage must be small, otherwise it may cause short circuits, leading to

battery thermal runaway. 1. Test Section 1.1 Instruments and Fixtures BOYI 2025-001 electronic universal testing machine ；

500N pneumatic foil specialized tensile fixture 1.2 Analysis Conditions 。

Test temperature: around 20°C room temperature Load sensor: 1000N (class 0.5)

Test fixture:

Pneumatic foil specialized tensile fixture Test speed: 50mm/min

1.3 Samples and Treatment

Two groups of lithium battery separator samples with thicknesses of 7μm and 12μm were evaluated, respectively tested in the machine direction (MD) and transverse direction (TD). Table 1 summarizes the list of these samples.

2. Test Introduction

This test used the BOYI 2025-001 electronic universal testing machine and 500N pneumatic foil specialized tensile fixture to perform room temperature tensile testing on the separator membrane. (Figure 1. Test system composition and fixture sample close-up) The fracture test was conducted at a crosshead displacement speed of 50mm/min. 500N Figure 1. Electronic universal testing machine and pneumatic foil tensile fixture

3. Results and Conclusions

3.1 Test Results